In the manufacture of tires, typically used for automobiles and trucks, a green tire (one which is already formed/built, but not cured) is placed in an open mold within a conventional tire curing/molding machine. The green tire is positioned about a deflated bladder disposed within the mold section of the curing machine. Subsequently, the mold section is closed and sealed, the bladder is inflated against the interior surface to force the exterior surface of the green tire against the heated mold walls whereby the green tire receives a tread pattern. After some period of time, the green tire is cured, the inflatable bladder is deflated, the mold is opened, and the now cured tire ejected from the mold. The inflatable bladder may stick to the interior surface of the cured tire after the curing operation and deflation of the bladder. Consequently, a machine operator would manually separate the bladder from the interior surface of the cured tire so that the cured tire could be ejected and a new green tire inserted into the curing machine. This causes a costly and time consuming delay in the tire manufacturing process.
To lessen or eliminate this delay, a machine operator may spray a coating of bladder release agent on the interior surface of the green tire and/or the bladder with a paint gun prior to loading the green tire within the curing machine and inflating the bladder. While this technique may ensure that the bladder separates from the interior surface of the cured tire when curing is complete, it may still required a delay for the machine operator to individually spray each tire and/or bladder before the green tire is loaded into the curing machine. Further, the machine operator must carefully apply the bladder release agent to ensure that the bladder release agent completely covers the interface between the interior surface of the green tire and the bladder so that no part of the bladder sticks to the cured tire. Beside being a costly, time consuming process, which slows the production of tires, it may also be subject to operator error. This error may occur randomly with inconsistencies in application of the bladder release agent and sticking of part of the uncoated sections of the tire to the bladder.
Further, excess bladder release agent may accumulate on and contaminate the mold walls because of the tendency for dirt to cling to the viscous bladder release agent. This contamination may produce inconsistent heat transfer between the bladder and the interior of the green tire leading to undercured portions of the tire and, ultimately, accumulation of costly scrap. Additionally, this contamination may necessitate stoppage of the tire production line to clean the molds. Further, this method may not be adaptable to modern manufacturing techniques where the entire process is conducted by automated machines and/or robots.
A system, apparatus, and/or method of curing a green tire to prevent the sticking of the bladder to the interior of a cured tire, without a manual step by a machine operator may be desirable. It is an object of the present invention to provide such a system, apparatus, and method for applying a bladder release agent between a green tire and a bladder in a tire curing machine thereby obviating delay/scrap issues of conventional techniques.